Barnett’s body was found in a vehicle in a Holiday Inn parking lot in Charleston on Saturday, police said. One day earlier, he testified about the string of problems he says he identified at Boeing’s plant where he once helped inspect the 787 aircraft before delivery to customers.

Police say officers were sent to the hotel to conduct a welfare check after people were unable to contact Barnett, who had traveled to Charleston to testify in his lawsuit against Boeing.

“Upon their arrival, officers discovered a male inside a vehicle suffering from a gunshot wound to the head,” police said in a statement sent to NPR. “He was pronounced deceased at the scene.”